My Home Ideas

Special Offers

Be the first to know about This Old House contests, sweepstakes, and events and receive special offers and promotions from your favorite home improvement brands. We'll even send you regular reminders to enter our sweepstakes.

If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

Insulating in Crawl Space

I am wondering what the best way to insulate between the first floor and the dirt. We have a 1830s home that sits anywhere from 6 inches to 2 feet from the dirt. A quarter of the space is a full height cape cod cellar which house all the usual mechanics of the home. Termites (which are controlled) are a huge issue here, so I am afraid to cover up the joists.

Re: Insulating in Crawl Space

Batting with cheap wire supports every 10 inchs or so. you can access areas easily to run wire etc or what ever you need.
and put down plastic on the ground and if can afford it put down some crush and run on the dirt first.

Re: Insulating in Crawl Space

Be sure to put good insulation around the rim joist. This will help trap warm air against the bottom of the floor. You won't need heavy or thick batting between the joists, just keep the vapor barrier up and the batts at the bottom of the joists. 3.5" batts with a 5-6" air space above them and well insulated rim joists will keep your floors nice and warm.

Another option would be 1" styrofoam panels attached to the bottoms of the joists, but those styrofoam panels are a bit pricey.

Re: Insulating in Crawl Space

Originally Posted by Infraredsurvey.com

Batting with cheap wire supports every 10 inchs or so. you can access areas easily to run wire etc or what ever you need.
and put down plastic on the ground and if can afford it put down some crush and run on the dirt first.

Why would you put down crush and run in the crawl space? We have dirt and 6M plastic on top. Does the gravel help keep the moisture down? We live on a river bed w/ the river about 100ft from our home so the water table is a serious concern. Our subfloor is 32" above ground surface. Thanks!

Re: Insulating in Crawl Space

Re: Insulating in Crawl Space

Crush and run or sand or some form of drainage material will help any condensation that may accumulate on the plastic.-just a little better than dirt.here is a thermal pic of a poorly insulated crawl all the red is heat loss from above and the reason your are smart enough to do what you are asking advise about.www.infraredsurvey.com